Polymers, in general, are ubiquitous in electronic devices; they are in capacitors, in batteries, in PCB substrates, in packing, in sensors, and in flexible conducting traces, just to name a few.  Network polymers refer to highly interconnected polymers that are highly stable under heating and to chemical exposure. Most epoxies, polyimides, and elastomers are network polymers. The important class of electronic material is, however, often one of the most misunderstood and misused substance in consumer electronics.  In this 3-hour crash course, I will provide (i) basic concepts that are necessary to understand the characteristics of network polymers, (ii) understanding thermoset polymers (such as electronic packaging and adhesive materials), (iii) understanding elastomers and gels (substrate for stretchable electronics), and (iv) their applications in stretchable electronics and soft robotics.  The lecture will build up the story from polymeric materials used in conventional electronic devices, such as electrical insulators, adhesives, capacitor dielectrics, wire/cable materials.  Then, the stories about specialty polymers, such as conductive conjugated polymers, ferroelectrics, liquid crystals, and ionomers, will be told.  Finally, the story will reach to the current trend of flexible, stretchable and printed IoTs, with an outlook of future technologies.